Approach to Altered Mental Status: Delirium, AMS Evaluation

[00:00:01]Hello, this is Eric Strong from Stanford University and Strong Medicine. Today I'll be discussing an approach to altered mental status, focusing on acutely altered mental status.

[00:00:13]The first thing to discuss is the fact that the term altered mental status is imprecise and should generally be avoided when describing patients to colleagues and in documentation.

[00:00:25]The reason that is in common usage within medical settings, the term alternal status is used as a label for quite distinct clinical syndromes with different causes and different treatments. These distinct syndromes can be differentiated from one another based on several key characteristics.

[00:00:44]One characteristic is wakefulness or how awake or arousable the patient is.

[00:00:50]Another is alertness, which is a qualitative assessment of whether the patient can demonstrate an awareness of themselves and of others around them. In most circumstances, consciousness requires both wakefulness and alertness.

[00:01:06]So, a person whose eyes are open but staring at the ceiling without being able to respond to others, they might be considered awake, but in almost all circumstances, not conscious. This is what's seen with patients experiencing what's called a persistent vegetative state. Now, there are certainly rare exceptions to this, such as the lockin syndrome that I'll come back to in a few minutes. But generally speaking, to say a patient is conscious, they must demonstrate purposeful movement or thought, or at least react in some way to the external world, such as responding to someone's voice, reaching for an object, or even just tracking another person's movement with their eyes as that other person walks across the room. Another characteristic to assess is attention. This describes how well a person can stay on task. Some quick bedside tests of attention include the ability to follow a three-step command or reciting either the days of the week or months of the year backwards. One that's less commonly done, but which I personally like is to have the patient either raise their hand or squeeze the examiner's hand every time a specific letter is said during a recitation of random letters. Three other key characteristics are orientation, thought process, and thought content. Orientation is whether the patient can state where they are, what the date is, and what the current situation is. For example, being able to state that they were brought to the ER by their family because they had a fever.

[00:02:37]A patient's thought process refers to the relevance, organization, and coherence of their thoughts. For example, whether the patient can stay focused when answering a question or they kind of veer off into an irrelevant but still relatively coherent tangent or is jumping so quickly from one thought to the next that you can't follow anything they're saying. Thought content includes the presence of hallucinations and delusions.

[00:03:05]The first two of these characteristics on this list can be framed as the level of consciousness. To contrast that with the last three being the content of consciousness, attention does not neatly fall into either one. These characteristics are not fully independent of each other. As just one example, a patient experiencing decreased wakefulness may find it difficult to remain oriented to time since the passage of time is difficult to gauge when one is extremely drowsy.

[00:03:36]The last key characteristic that differentiates syndromes of alternation is the temporal pattern. For example, are abnormalities fluctuating from one hour to the next or are they consistent across time?

[00:03:51]Now let's look at the specific syndromes. The first is delirium. The hallmarks of delirium are impairments of orientation, thought process, and thought content as well as a fluctuating course. So in the morning, a patient might not be able to state where they are or an approximate date. And then in the afternoon, they might be fully aware of both those things, but answers to more complex questions are not clear or linear. And then at night, they are disoriented again, perhaps now with some visual hallucinations or a delusion that the nurses are trying to kill them. How the patient looks and acts at the bedside is changing throughout the day.

[00:04:31]Patients with delirium always have impaired attention, but their level of wakefulness and alertness can be reduced, normal, or even higher than normal. Delirium with reduced wakefulness and alertness is called hypoactive delirium, while that with increased wakefulness is predictably called hyperactive delirium, often with increased psycho activity, such as wandering at night or combative behavior. As a general rule, hypoactive delirium is more difficult to identify than hyperactive delirium and is frequently misidentified as dementia, depression or as the next syndrome, somnolence.

[00:05:10]The hallmark of somnolence, sometimes imprecisely referred to as decreased mental status, is that wakefulness, alertness, and attention are all reduced. However, unlike hypoactive delirium, the patient is non fluctuating or consistent. Orientation may be impaired depending on severity and ideology, but thought process and content are usually normal. Patients with a somulent subtype of altermental status do not hallucinate or have delusions about their situation.

[00:05:41]The last subtype is one of agitation and psychosis. Keeping in mind that these two terms are not synonyms, but they have enough shared features to consider them one relatively broad syndrome. In this case, wakefulness and alertness are always increased, what is referred to as hyperarousal.

[00:05:59]There is also increased psychoot activity such as pacing around the room or ward and speaking more quickly than normal. Attention is usually reduced.

[00:06:09]Orientation, thought process, and thought content can all be either normal or impaired. The use of the term psychosis rather than agitation specifically implies the patient is experiencing prominent hallucinations, delusions, and/or disorganized thought such as incoherent rambling. In most contexts, the use of the word psychosis does not imply that the patient necessarily has an underlying primary psychiatric disease.

[00:06:36]The pattern of abnormalities in states of agitation and psychosis can be either fluctuating or consistent depending on the underlying cause.

[00:06:45]As you may have already noticed, there may be relatively little clinical distinction between hyperactive delirium and a fluctuating psychosis.

[00:06:54]One can graph these three syndromes by looking at the level of consciousness versus the content of consciousness.

[00:07:01]Somnilence has decreased level of consciousness with a content of consciousness that can be either normal or modestly impaired. Agitation and psychosis have impaired content of consciousness but with a normal or even higher than normal level of consciousness.

[00:07:17]With delirium, hypoactive delirium can look similar to somulance particularly if the patient is only examined at a single point in time. While as mentioned hyperactive delirium can look similar to agitation and psychosis, there is a frequent comparison made in textbooks and medical school lectures between delirium and dementia. In delirium, the onset is acute to subacute, roughly meaning over hours to a week or so. While in dementia, the onset is chronically progressive over months to years, though sometimes with step-wise declines in level of functioning, typically following acute medical illnesses.

[00:07:55]Signs in delirium fluctuate over time while they are relatively consistent in dementia.

[00:08:01]Finally, delirium is usually reversible while dementia is irreversible.

[00:08:08]Importantly, while pure delirium is easy to distinguish from pure dementia, the two are not mutually exclusive and a common diagnostic challenge is determining whether just one or both are present. a distinction which almost always requires collateral information from someone who knows the patient outside of the health care setting. The presence of pre-existing dementia also increases the risk of developing delirium when additional pathology is introduced. For example, when a patient with dementia has a urinary tract infection or is started on steroids.

[00:08:45]Developing a diagnostic framework for syndromes of altermentation is tricky because the three primary syndromes have overlapping but not identical lists of ideologies.

[00:08:57]However, they generally map to the same broad categories. An easy way to remember these categories is with a pneumonic I first saw on the excellent clinical problem solvers website. Mist.

[00:09:10]M for metabolic, I for infection, S for structural, meaning a physical problem in the brain, usually a space occupying lesion, and T for toxin, though toxin also includes medications.

[00:09:24]In addition, there is a long list of miscellaneous causes which don't fall neatly into one of these four categories.

[00:09:31]Before doing a deep dive into each category of pathology, we can first make some generalizations about which categories tend to cause which syndromes. The most common causes of delirium tend to be infections, sedative withdrawal and from the miscellaneous category, hospitalacquired delirium. The most common causes of sulence are metabolic CNS infections, any cause of increased intercraanial pressure and either sedative intoxication or stimulate withdrawal. And the most common causes of agitation and psychosis are CNS infections, steroids, stimulant and hallucinogen intoxication, and sedative withdrawal. and also causing agitation and psychosis are of course primary psychiatric disease such as schizophrenia and the mania of bipolar disease. Now let's talk about the ideologies more specifically and it is a long list. It's probably the largest and most diverse diagnostic framework in medicine.

[00:10:30]Starting with the metabolic category, we have electrolytes which includes derangements of sodium, calcium, glucose and pH as well as hypercapnea or high partial pressure of carbon dioxide.

[00:10:43]Isolated derangements of potassium and low pCCO2 are not notable causes of altered mentation.

[00:10:51]Other metabolic causes include hypoxmia, shock from any cause, liver and renal failure known as hpatic and encphylopathy and uremic encphylopathy respectively.

[00:11:02]Worickes encphylopathy is a condition caused by thymine deficiency which classically presents with a triad of confusion, unstable gate and ocular motor pathology such as nestagmas. It's most often observed in patients with chronic heavy alcohol use.

[00:11:21]Thyroid disease either hypo or hyperthyroidism can cause altermentation. Though the form of altermentation looks very different between those two with severe hypothyroidism causing depression, fatigue and somnilence while hyperyroidism can cause anxiety and agitation.

[00:11:40]Severe adrenal insufficiency is also associated with a variety of cognitive and psychiatric manifestations.

[00:11:48]The next broad category is infection.

[00:11:50]These can be subdivided into infections of the central nervous system such as menenitis which is an infection of the protective membranes surrounding the brain and spinal cord and encphylitis which is an infection of the brain itself and nonS infections which most commonly include pneumonia, urinary tract infections and bacteria.

[00:12:14]Though any infection if severe enough can cause delirium.

[00:12:19]Structural causes of altermentation include eskeemic stroke, intraraanial hemorrhage which can be epidural, subdural, subaractid, intraaranimal or intravententricular and masses like tumors and abscesses.

[00:12:37]And then there are the so-called toxins such as many medications which can cause altermentation particularly in the elderly or when taken in combination a situation known as polyfarm pharmacy. A non-comprehensive list of the most common culprit medication classes include both opiate and nonopiate pain medications. Among the more common nonopiate pain meds to cause confusion are tramodol and gabapentin.

[00:13:05]Other meds include steroids, antiolinurgics, antihistamines, antiscychotics which are specifically associated with the life-threatening condition neurolleptic malignant syndrome, benzoazipines and related sedative hypnotic drugs like ambient and muscle relaxants like cyclloensziprne and blephin.

[00:13:26]Valproic acid is associated with hyperamonymia which can lead to altermentation and an increasing recognized phenomenon of sephopime induced neurotoxicity which is most often seen in patients with concurrent renal dysfunction.

[00:13:41]Just about any true toxin can cause altermentation most notably alcohol elicit drugs toxic alcohols like methanol and ethylene glycol and carbon monoxide poisoning.

[00:13:55]Last in this category is a potentially life-threatening condition called serotonin syndrome, which is the consequence of either medications or elicit drugs that increase the activity of serotonin in the brain, particularly anti-depressants, empetamines, and ecstasy and particularly when such substances are used in combination.

[00:14:17]Serotonin syndrome presents with a combination of autonomic dysfunction, neuromuscular excitation, and altered mental status.

[00:14:27]As mentioned, there are many other ideologies which don't fall neatly into the mist pneummonic and which I'm going to place into a miscellaneous category.

[00:14:37]The most common condition in this category is, as mentioned a few minutes ago, hospitalacquired delirium, which is a form of delirium that occurs in hospitalized patients. thought secondary to a combination of acute illness, uncontrolled pain, disrupted sleep wake cycles, side effects from new medications, and in some cases, sensory deprivation. For example, when a patient who normally wears glasses or contact lenses, or a hearing impaired patient who normally uses a hearing aid does not have access to those devices.

[00:15:11]Emergence delirium is a short-lived period of confusion, agitation, and disinhibition that can occur in a patient during the transition from general anesthesia to full wakefulness typically seen in the post anesthesia care unit. There is also an entity called post-operative cognitive dysfunction manifesting primarily as relatively subtle memory deficits most common after cardiac surgery and which can last for several months.

[00:15:39]Other miscellaneous causes include psychiatric disease such as inadequately controlled schizophrenia, bipolar disorder, or catatonia.

[00:15:49]Patients will often be confused for a brief period of time following a generalized seizure, something called the postal state.

[00:15:56]Patients can also have a condition called non-convulsive status epilepticus which they are experiencing extremely frequent or even continuous seizures but for some reason they're not physically convulsing their muscles so the seizure is not externally apparent.

[00:16:14]Alimoimmune disease can include autoimmune encphilitis including paranoplastic encphilitis, a condition called Hashimoto's encphylopathy which is associated with thyroid disease but which has a distinct pathogenesis, lupus and isolated CNS vasculitis.

[00:16:33]Wilson's disease a genetic disease of copper overload classically causes a combination of liver failure and a variety of neuroscychiatric abnormalities.

[00:16:43]the similar diseases of hypertensive encphylopathy and the posterior reversible encphylopathy syndrome, heat stroke and hypothermia and a condition called transient global amnesia in which as the term implies an individual experiences a brief total or near total loss of memory without other significant cognitive changes and without an identifiable cause. The condition will typically last less than a day before gradually improving. Its pathogenesis is unknown.

[00:17:18]The last category in this extensive framework to discuss are the mimics of acutely altered mentation. The first in this category is a phenomenon called sundowning. Now sundowning is the commonly observed worsening of dementia symptoms in the evening particularly behavioral disturbances.

[00:17:38]Although sundowning is an alteration from the patient's condition and behavior as compared to the daytime, I include it as an AMS mimic because it's not an alteration from the patient's longitudinal baseline and it's not due to any additional pathology beyond the underlying dementia.

[00:17:57]However, distinguishing some downing from a new acute delirium in a newly admitted patient with dementia is very challenging unless there is a family member at the bedside who can clarify whether the observed behavior is or is not typical for that patient when they are at home or wherever residential facility they typically stay.

[00:18:21]The remaining conditions in this category of AMS mimics are those in which the patients appear to be confused, delirious or somalant when their higher cognitive function is mostly or completely intact.

[00:18:35]This includes disarthria in which uh there is an impairment in the tongue, lips and oral ferings's ability to phonate words.

[00:18:44]Aphasia is an impairment of language which can be mistaken for confusion.

[00:18:48]Particularly the subtype of Warick's aphasia, not to be confused with Warick's encphylopathy.

[00:18:54]In Warick's aphasia, speech has normal speed and cadence, but is composed of seemingly nonsense words or words that just don't make sense together. This can be distinguished from other disorders because patients with isolated worn aphasia will display normal cognitive function with any task or behavior that does not involve language.

[00:19:19]Locked in syndrome which was mentioned at the beginning of the video is a horrific condition in which damage to the lower brain and/or brain stem leaves a patient with virtually no voluntary control of their muscles aside from eye movement. but with fully intact level and content of consciousness.

[00:19:39]And finally, the last alternation mimic is mingering, meaning the patient is deliberately faking their condition for secondary gain, such as having a warm place to sleep or avoiding jail.

[00:19:54]When it comes to which of these many ideologies are among the most common, as previously mentioned, it depends on which subtype of alteration we're considering. Among hospitalized adults in the US, common causes of delirium are non CNS infections, a large variety of medications, alcohol withdrawal, various elicit drugs, and hospitalacquired delirium.

[00:20:17]Common causes of somnolence are hypoglycemia, hypercapnea, shock, liver failure, intraraanial hemorrhage, opiates, alcohol intoxication, and various elicit drugs.

[00:20:31]And common causes of agitation and psychosis are hypoxmia, steroids, alcohol withdrawal, various elicit drugs, schizophrenia, and mania.

[00:20:44]There are two big challenges with evaluating a patient presenting with some form of altermentation.

[00:20:50]The first, as you just saw, the diagnostic framework is huge and it includes conditions that span from the relatively benign like UTI and benadrol toxicity to imminently life-threatening problems like menitis and incraanial hemorrhage. The second challenge is that obtaining a reliable history directly from the patient is not possible and particularly when the patient is hyperactive or agitated, a physical exam may be more difficult and limited than normal. So there is necessarily a greater reliance on labs and imaging to narrow down the differential diagnosis for patients presenting with altermental status than there is for most other symptoms. and even imaging can be impossible without sedation for the agitated patient. Other unusually important components of the evaluation of the altered patient are reviewing the patient's past medical chart if it's available and obtaining collateral history meaning history about the patient given to you by the patient's family, friends or neighbors.

[00:21:55]So what are the critical features of the history that you should attempt to obtain? The first is the time course of the altermentation. Meaning, how long has this been going on for? Did the changes happen all at once or did it progressively worsen over time? And are the symptoms consistent or fluctuating?

[00:22:15]Are there concurrent symptoms such as fever and chills, cough, dysnia, dysura, neck pain or neck stiffness, headache or nausea?

[00:22:25]What's the patient's past medical history? For example, do they have a history of diabetes, liver or renal disease, a seizure disorder, or dementia?

[00:22:34]Their past psychiatric history, a medication in substance use history are both critically important.

[00:22:42]And do they have risk factors for delirium specifically in addition to dementia? These risk factors include acute medical illness, sensory impairment, sleep deprivation, immobility, malnutrition, and inadequate treatment of pain.

[00:22:58]Regarding the exam, presentations of acutely alter mental status are among the few in which a complete head-to-e exam is truly indicated for as much as the patient is able to cooperate.

[00:23:11]Key lab tests in the evaluation include serum glucose, a complete metabolic panel and blood count, a urinal analysis and urine culture, blood cultures in most circumstances, and a urine tox screen and blood alcohol level in most circumstances.

[00:23:30]Depending on the results of the above, one can consider a TSH, lactate, ammonia, and a blood gas. Regarding the interpretation of a modestly abnormal TSH, you need to keep in mind that TSH can be affected by acute non-thyroidal illness. And regarding the blood gas, usually a Venus gas is sufficient unless carbon monoxide poisoning is suspected, in which caseimemetry is the appropriate test.

[00:23:58]Other tests commonly used in the evaluation of states of altermentation include a chest X-ray if pneumonia is a possibility. Brain imaging usually starting with a non-contrast head CT.

[00:24:09]Lumbar puncture is also sometimes done if the workup including imaging is unrevealing.

[00:24:15]In addition to all this, there are several scales and scoring systems that are frequently discussed when evaluating patients with alternation.

[00:24:23]One is the Richmond agitation sedation scale which is a 10-point scale ranging from plus4 for combative patients who are imminently dangerous to the healthcare staff to neg five for patients who are completely unarousable to voice or physical stimulation.

[00:24:39]The Glasgow Comoma Scale grades three behaviors, eye opening, verbal response, and motor response that come up with a number ranging from three for a fully comeosse patient to 15 for normal cognition. The GCS provides information about prognosis and in some cases can guide decisions about intubation of patients with acute neurologic impairment. However, in isolation, it provides no useful information about diagnosis.

[00:25:08]In addition to these previous scales, there are a number of other scored cognitive assessments that are sometimes used in this context, including the Montreal Cognitive Assessment or MOCA, the Mini Mental State Exam or MMSSE, and the so-called mini COG. However, these tests are not appropriate for the assessment of acutely altered mental status in hospitalized patients.

[00:25:32]Instead, their proper use is primarily to screen for and grade the severity of dementia and other forms of chronic cognitive impairment in the outpatient setting. Once again, do not perform mochas or many mental exams in patients in the ER or hospital.

[00:25:51]Now, when it comes to a diagnostic algorithm for acute mental status, despite the different subtypes with different lists of ideologies, the initial steps to determining a diagnosis are remarkably similar. Let's take a look.

[00:26:05]Before even starting the history, there are a few very time-sensitive things to address. First assess the ABCs that is the patient's airway, breathing or the presence, frequency and depth of respirations and circulation that is the pulse and blood pressure. Immobilize the spine if there's a history of trauma.

[00:26:25]Because it's so fast to check and hypoglycemia is imminently life-threatening, check the serum glucose with a glucometer, even if the patient is not known to be a diabetic.

[00:26:37]If heavy alcohol use is suspected, empiric thymine for treatment of warnes and sephylopathy which can acutely worsen if glucose is given in the absence of thymine. And if the patient is somnolent and has a low respiratory rate, give empiric nlloxxone to reverse possible opiate overdose and consider intubation.

[00:26:57]Once those things are completed, then proceed with a more thorough evaluation, including history and exam, a complete metabolic panel, blood count, blood gas, blood cultures, UA and urine culture, urine tox screen, alcohol level, and serum drug levels of any of the patients prescribed medications, though this is not readily available for most meds.

[00:27:19]A chest X-ray can reveal pneumonia and a non-contrast head CT should be performed unless the diagnosis is already readily apparent from the above.

[00:27:30]For most patients, this set of data will already establish or strongly suggest a specific ideology in which case continue with a focused evaluation of that ideology and initiate treatment.

[00:27:43]On the other hand, if the ideology is not yet established, ask if a lumbar puncture is indicated. Considerations here include whether there is a fever, the patient has a headache, unexplained luccoytosis, menial signs on exam like neck stiffness, and if the patient is immuno compromised.

[00:28:02]If enough of these considerations point towards LP, then do one. If the ideology is established or suggested, great. But if either an LP is not indicated or the LP was non-diagnostic, then you should continue to the next set of diagnostic tests which can include a TSH, ammonia level, thamine level, though this test is not particularly sensitive for worn and sephylopathy and a serum osmalerity to identify the ingestion of toxic alcohols. Keeping in mind that serum osmalerity is best run on the first blood sample following presentation rather than on a blood sample from many hours later. Depending on circumstances, one can consider a brain MRI, EEG, and either a morning cortisol or court stem test to identify adrenal insufficiency.

[00:28:53]If an ideology is still not established and the patient has not yet spontaneously improved, which does happen sometimes, you're moving into rare ideology territory, you should perform an LP if not already done and consider looking for paranoplastic disease, autoimmune disease, Wilson's disease, and causes of rapidly progressive dementia. And when I say consider these rare diagnoses, that's what I mean. you don't necessarily need to test for them if the data you've already obtained is clearly inconsistent with them. However, in particular, I would think about paranoplastic and sephilitis in which the primary tumor underlying the disease is not yet otherwise clinically evident. Although paraneoplastic and sephilitis is rare among patients ultimately diagnosed with it, it is common for the neurokcognitive findings to have preceded the cancer diagnosis.

[00:29:48]The key takeaway points for this video.

[00:29:51]Alter mental status is an imprecise term that should be avoided in favor of delirium, somnolence, agitation or psychosis.

[00:30:00]The altermental status syndromes can be distinguished by level of consciousness, content of consciousness and their temporal pattern.

[00:30:10]Delirium, sombrillance, agitation, and psychosis all have broad modestly overlapping diagnostic frameworks, but medications, alcohol, and elicit drugs are shared common causes.

[00:30:24]And last, the history and physical exam, conventional labs, and headct will identify the majority of ideologies. If these are insufficient, lumbar puncture, brain MRI, EEG, and more specialized blood tests may be indicated.

[00:30:41]Thanks for watching this video on an approach to altermental status. If you found it helpful, please consider subscribing to the channel and checking out the rest of the series on an approach to symptoms.